1. Field of the Invention
The present invention relates generally to roof constructions, and more particularly to a composite roof structure and a corresponding method for fabricating the composite roof structure, using a non-cellular adhesive material for securing the roof insulation to the roof substrate and an upper, flexible roof membrane comprising a sheet of flexible rubber-like material preferably with fleece-like matting secured to the underside thereof or membrane with an underside prepared for adhesive attachment, to a roof substrate or roof insulation.
2. Description of the Prior Art
Many different roofing systems have been proposed in the past, ranging from simple asphalt/gravel roofs to more sophisticated structures making use of synthetic resin materials. It has also been known in the past to construct roofs using foamed, cellular adhesive materials, such as foamed, cellular polyurethane adhesives. However, they present a number of problems. First, the foamed, cellular synthetic resin adhesive materials tend to rise and forms bulges under the roof insulation or at roof membrane seam areas, thus making difficult and laborious to control evenness of the finished roof. They provide little resistance to low temperatures and become friable when are applied at temperature below 40xc2x0 F. Furthermore, the foamed, cellular synthetic resin adhesive materials have relatively low tensile strength, thus provide very low puncture resistance to the finished Roof. The foamed, cellular adhesives have limited shelf life.
It has also been known in the past to construct roofs using synthetic rubber membranes formed from EPDM rubber. In such constructions, an adhesive substance is first applied to a substrate and allowed to partially dry. This drying causes volatile gases which are mostly pollutants, to escape into the atmosphere. Even at best, These roof membranes tend to be poorly attached and many times suffer from damage in usually encountered moderate winds.
The present invention overcomes the problems outlined above and provides a greatly improved composite roof structure broadly including a layer of non-cellular adhesive material adapted to be secured to a substrate, and various insulation layers adhered with the same non-cellular adhesive along with a flexible roof membrane attached to the adhesive. The roof membrane includes a sheet of flexible material (e.g. TPO rubber) having a fleece-like matting secured to the underside thereof or other prepared underside thereof. It has been found that the use of such matting permits the roof membrane to be strongly adhered to the adhesive, with the matting being at least partially embedded within the adhesive itself.
In particularly preferred forms, the non-cellular adhesive material is in the form of a non-cellular polyurea polyurethane adhesive material. The non-cellular adhesive layer has a thickness after solidification of at least about {fraction (1/16)} inch, and more preferably from about {fraction (1/16)} to xc2xc inches. Furthermore, in order to facilitate installation, the non-cellular adhesive material is initially in the form of a liquid and has a fast initial set and relatively slow subsequent final cure. Advantageously, the non-cellular polyurea polyurethane adhesive is a two-component system having polyol/diisocyanate components.
The flexible roof membrane preferably comprises a synthetic rubber (such as TPO, EPDM or the like) sheet having a thickness of from about 40-70 mils, with fleece-like non-woven polyester matting having a thickness from about 40-80 mils secured thereto or membrane with an underside prepared for adhesive attachment. While the TPO/polyester membrane is preferred, the invention is not so limited. Rather, use can be made of a wide variety of thermoplastic or thermosetting elastomeric flexible materials having a selected textile matting (e.g. polyolefinic) secured to the underside thereof or membrane with an underside prepared for adhesive attachment.